Definition
A criminal conspiracy is an agreement between two or more people to commit an unlawful act, combined with the intent to carry it out. In many jurisdictions, the prosecution must also prove that at least one member took an overt act in furtherance of the agreement. Conspiracy is an inchoate crime, meaning it punishes the agreement itself, even if the planned offense is never completed.
Legal Meaning
Conspiracy is one of the most powerful tools in a prosecutor's arsenal because it allows criminal liability to attach at an early stage—when people agree to commit a crime—rather than waiting for the crime to be carried out. The law treats group criminal planning as especially dangerous, reasoning that collective action makes serious crimes more likely to succeed and harder to abandon.
The core of every conspiracy is the agreement. Two or more people must agree, expressly or by their conduct, to pursue an unlawful objective, and they must intend both to enter the agreement and to achieve its criminal goal. The agreement does not have to be written or formal; it can be inferred from the parties' coordinated behavior.
Many jurisdictions add a second requirement: an overt act taken by at least one conspirator in furtherance of the agreement. The overt act need not be a crime by itself—buying supplies, scouting a location, or making a phone call can suffice. Some conspiracy statutes, however, require no overt act at all. Conspiracy is defined by statute, and the elements, scope of liability, and penalties vary by state and under federal law, where broad conspiracy statutes are frequently used in complex prosecutions.
Key Points
- Conspiracy is an agreement between two or more people to commit an unlawful act
- The conspirators must intend to enter the agreement and to achieve its criminal objective
- Many jurisdictions also require an overt act in furtherance of the agreement
- The overt act need not itself be a crime—even a minor preparatory step can qualify
- Conspiracy is an inchoate offense and can be punished even if the planned crime is never completed
- Co-conspirators may be liable for foreseeable crimes committed by other members in many states
- Withdrawal may be a defense if a conspirator affirmatively abandons and communicates it
- The elements, scope, and penalties vary by state and under federal law
Real-World Example
Three friends agree to rob a bank. They intend to go through with it, divide responsibilities, and one of them rents a getaway car and buys ski masks. Even if police arrest them before they ever enter the bank, all three can be charged with conspiracy to commit robbery. The agreement, combined with the intent to carry it out and the overt act of renting the car and buying the masks, completes the crime of conspiracy in a jurisdiction that requires an overt act.
If the robbery had actually been completed, the three could be charged with both the conspiracy and the robbery itself, and under co-conspirator liability rules, each might be responsible for foreseeable crimes committed by the others during the robbery.
Elements and Features of Conspiracy
| Element / Feature | What It Means |
|---|---|
| Agreement | Two or more people agree to pursue an unlawful objective |
| Intent | Intent to join the agreement and to achieve the criminal goal |
| Overt act | A step toward the crime, required in many but not all jurisdictions |
| Inchoate offense | Punishable even if the planned crime is never completed |
| Co-conspirator liability | Liability for foreseeable crimes of other members in many states |
| Withdrawal | A possible defense requiring affirmative abandonment and notice |
Co-Conspirator Liability
One of the most significant consequences of a conspiracy is that members can be held responsible for the acts of their co-conspirators. Under a widely recognized doctrine, a conspirator may be liable for crimes committed by other members of the conspiracy that were reasonably foreseeable and were committed in furtherance of the agreement, even if that conspirator did not personally participate in or know about the specific act. The breadth of this liability varies; some states apply it expansively, while others have narrowed or rejected its broadest form. This is why joining even a minor role in a criminal plan can expose a person to serious additional charges.
Withdrawal and Other Defenses
Because conspiracy is based on an agreement, a defendant may argue there was never a genuine agreement, or that they lacked the intent to commit the underlying crime. Withdrawal is another potential defense: a conspirator who takes affirmative steps to abandon the conspiracy and communicates that abandonment to the other members may, in some jurisdictions, limit or end their liability—particularly if they act before an overt act or in time to thwart the crime. The rules differ by jurisdiction, and the related crimes of fraud and the inchoate offenses of attempt and solicitation often appear alongside conspiracy charges.
Related Terms
Accused of Conspiracy?
Conspiracy charges can sweep in minor players. An experienced defense attorney can protect your rights.
Explore Criminal DefenseWhen You Need a Lawyer
Conspiracy charges are complex and can carry penalties as serious as the underlying crime. An experienced criminal defense attorney can:
- Explain how conspiracy is defined in your state or under federal law
- Challenge whether a genuine agreement and the required intent can be proven
- Argue that no overt act occurred where the jurisdiction requires one
- Raise withdrawal, lack of knowledge, or other available defenses
- Limit your exposure to crimes committed by other alleged co-conspirators
- Negotiate with prosecutors, who often use conspiracy charges as leverage in plea discussions
Because conspiracy law is technical and varies by jurisdiction, consult a lawyer as soon as you learn you may be implicated. For an overview of how criminal cases proceed, see our guide on civil vs. criminal cases.
Frequently Asked Questions
What are the elements of criminal conspiracy?
Conspiracy generally requires an agreement between two or more people to commit a crime and an intent to achieve the unlawful objective. In many jurisdictions, the prosecution must also prove that at least one conspirator committed an overt act in furtherance of the agreement. The overt act need not be illegal by itself; it simply has to be a step toward carrying out the plan. The exact requirements vary by state and under federal law.
Do you have to commit the crime to be guilty of conspiracy?
No. Conspiracy is a separate, inchoate offense that punishes the agreement to commit a crime, not the completed crime itself. A person can be convicted of conspiracy even if the planned offense was never carried out. In fact, many jurisdictions allow a defendant to be convicted of both the conspiracy and the underlying crime if it is completed.
What is the overt act requirement?
In many jurisdictions, conspiracy requires that at least one member of the conspiracy take an overt act in furtherance of the agreement. The overt act can be relatively minor and need not be a crime by itself, such as buying a tool, scouting a location, or making a phone call to advance the plan. Some conspiracy statutes, however, do not require any overt act, so the rule depends on the jurisdiction.
Can a conspirator be held responsible for crimes committed by other members?
In many jurisdictions, yes. Under co-conspirator liability, a member of a conspiracy can be held responsible for foreseeable crimes committed by other members in furtherance of the conspiracy, even crimes they did not personally commit. The scope of this liability varies, and some states have limited or rejected the broadest version of this doctrine.
Is there a defense of withdrawal from a conspiracy?
Withdrawal may be a defense in some circumstances. To withdraw effectively, a conspirator generally must take affirmative steps to abandon the conspiracy and communicate that withdrawal to the other members, and in some jurisdictions act before any overt act or in time to prevent the crime. The requirements and the effect of withdrawal vary by jurisdiction, so legal advice is essential.